Abstract
Purpose :
Corneal endothelial dystrophies are inherited bilateral disorders of the corneal endothelium that may result in corneal edema and vision loss. Multiple genes have been associated with different types of corneal endothelial dystrophies, including TCF4, COL8A2, ZEB1, SLC4A11, ATP1B1, KANK4 and LAMC1, but little is known about the interactions between these genes. We tested the hypothesis that TCF4 and ZEB1 as transcription factors are involved in the transcriptional regulation of the expression of COL8A1, ZEB1, ATP1B1, KANK4, LAMC1 (TCF4) and of SLC4A11 (ZEB1) in an immortalized human corneal endothelial cell line (HCEnC-21T), effectively linking various forms of corneal endothelial dystrophies as a series of connected disorders.
Methods :
We first re-analyzed the published ChIP-seq data of ZEB1 (ENCODE #ENCSR000BND) and TCF4/E2-2 (GEO #GSE76147) to look for binding peaks around the genes associated with the corneal endothelial dystrophies. Next, the peaks from ChIP-seq data were confirmed via ZEB1 ChIP-PCR or TCF4/E2-2 ChIP-PCR in HCEnC-21T with primers flanking the corresponding peak locations near the genes of interest.
Results :
In HCEnC-21T, we confirmed that ZEB1 binds to the SLC4A11 promoter at -1820 ± 50bp (relative to SLC4A11 (NM_032034.3) transcriptional start site (TSS)) and TCF4/E2-2 binds to the non-coding regulatory regions of ZEB1, COL8A2, ATP1B1, KANK4 and LAMC1. TCF4/E2-2 binds to: ZEB1 promoter and first intron at -210 ± 109 bp and +867 ± 83 bp (relative to ZEB1 (NM_030751.5) TSS); COL8A2 intron, two locations in COL8A2 3’ UTR, and one location downstream of the gene, at +25286 ± 57 bp, +28595 ± 91 bp, +29139 ± 84 bp and +31338 ± 87 bp (relative to COL8A2 (NM_005202.3) TSS); ATP1B1 promoter at -887 ± 70 bp (relative to ATP1B1(NM_001677.3) TSS); KANK4 first intron at +24697 ± 72 bp (relative to KANK4 (NM_181712.4) TSS); and three locations in LAMC1 first intron at +730 ± 90 bp, +16601 ± 59 bp and +47723 ± 64 bp (relative to LAMC1 (NM_002293.3) TSS).
Conclusions :
Various forms of corneal endothelial dystrophies can be categorized as a series of disorders affecting different genes in the same molecular pathway: TCF4/E2-2 transcriptionally regulates ZEB1, COL8A2, ATP1B1, KANK4 and LAMC1, while ZEB1 transcriptionally regulates SLC4A11.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.